To solve this problem, we need to identify the phase during which growth is maximum. Let's analyze each option:$\newline \bullet$Lag phase:$\newline$ - This is the initial phase of growth where cells are adapting to the environment.$\newline$ - There is little to no increase in cell number as cells are preparing for growth.$\newline$ - Therefore, growth is not maximum during the lag phase.$\newline \bullet$Senescence:$\newline$ - This is the phase where growth declines and cells begin to age and die.$\newline$ - Growth is not maximum during senescence.$\newline \bullet$Dormancy:$\newline$ - During dormancy, growth is temporarily halted or significantly slowed down.$\newline$ - Growth is not maximum during dormancy.$\newline \bullet$Log phase:$\newline$ - Also known as the exponential phase, this is where cells divide at a constant and rapid rate.$\newline$ - Growth is maximum during the log phase as the population size doubles at regular intervals.$\newline$Therefore, the correct answer is Option 4: Log phase.